Comparative analysis of fecal fat quantitation via nuclear magnetic resonance spectroscopy (1H NMR) and gravimetry.
BACKGROUND
Fecal-fat is typically measured by extracting lipid from homogenized feces with subsequent gravimetric/titrimetric analyses that are time-consuming and involve toxic solvents. Accordingly, an efficient and more safe method to quantitate fecal-fat is needed. The present objective was to adapt CEM SmartTrac technology (i.e. (1)H NMR) to rapidly (< 5 min) quantitate fecal-fat and compare (1)H NMR and gravimetric performance characteristics.


METHODS
(1)H NMR and gravimetric measurements of stool-fat were conducted using excess stool samples (72 h collection; n=107) homogenized to semi-liquid consistency prior to analyses.


RESULTS
The (1)H NMR method demonstrated acceptable linearity (R(2)=0.9999) and recovery (mean=105%) with imprecision (intra-assay CV=1.2-6.5%; inter-assay CV=1.8-5.8%) comparable to or better than gravimetry (intra-assay CV=1.0-17.2%; inter-assay CV=3.8-6.5%). Excellent correlation between fecal-fat quantitation by (1)H NMR and gravimetry (n=107; R(2)=0.983; y=1.0173x-0.6859) was exhibited; moreover, (1)H NMR demonstrated good sensitivity (92.3%), specificity (94.5%), negative-predictive value (92.9%) and positive-predictive value (94.1%) for malabsorption using the reference cut-off of < or = 7 g fat/24 h.


CONCLUSIONS
These data demonstrate that (1)H NMR permits rapid and safe quantitation of fecal-fat while maintaining acceptable performance characteristics, thereby supporting the utility of (1)H NMR as an alternative method to gravimetry for fecal-fat quantitation.
Korpi-Steiner
Nichole L
NL
Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 1st Street S.W., Rochester, MN 55905, United States.
Ward
Jennie N
JN
Kumar
Vivek
V
McConnell
Joseph P
JP
D019411:Clinical Laboratory Techniques; D005243:Feces / Q000737:chemistry*; D006112:Gravitation; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D012680:Sensitivity and Specificity; D017186:Titrimetry
D008055:Lipids